Showing papers in "Ultrasonics in 1984"

TL;DR: In this article, a mainly theoretical review of the physical aspects of the behavior of bubbles in sound fields is presented, including an equation for the radial motion, including the effects of liquid compressibility.

TL;DR: In this article, a general review of the mechanism of rectified diffusion is given, and the equations that describe the threshold acoustic pressure amplitude as well as the growth rate are presented.

TL;DR: In this paper, the chemical effects of high-intensity ultrasound on organic liquids are reported, and two very different chemical dosimeters have been used: radical trapping by diphenylpicrylhydrazyl and decomposition of Fe(C0)5.

TL;DR: In this article, a new ultrasonic technique for the determination of residual stresses in steel, intended to correct for the effects of variable texture and microstructure, is proposed, based upon the use of the compressional wave time delay in addition to the time delays of two orthogonally polarized shear waves used in the shear wave birefringence technique.

TL;DR: In this paper, the authors present a series of articles reviewing the physics and technology of acoustic cavitation, each contributed by a well-known specialist, covering background history, explaining the scope of the subject and defining terms in common use, and a list of the major sources of reference presently available, in the form of books, reviews and collections of papers.

TL;DR: In this paper, a selective review of the subject of acoustic cavitation inception is presented, including cavitation threshold measurements, the role of dirt or pre-existing bubble nuclei in Cavitation inception, radiation-induced acoustic cavitations, and a discussion of some unsolved problems such as cavitation thresholds in liquid helium and the effects of electric fields on thresholds.

TL;DR: In this paper, the authors consider the oscillations radiales de grande amplitude of bulles gazeuses and determination du temps de coalescence des bulles sous l'action de forces de rayonnement de pression.

TL;DR: In this paper, the authors derived expressions that determine both the transverse and longitudinal resolution of the SAFT process whilst taking into account the pulsed nature of the ultrasound used in the process.

TL;DR: The stimulating ability of focused ultrasound is applied to the diagnosis of neurological diseases, to the study of skin and tissue sensitivity in man, toThe diagnosis of hearing disorders, and to the introduction of auditory information to the deaf with certain forms of hearing pathology.

TL;DR: In this paper, an ultrasonic instrument for the accurate measurement of bolt stress is described, which is based on the pseudo-continuous-wave technique, uses carrier phase detection to track the frequency of the mechanical resonance of the bolt.

TL;DR: In this article, the acoustic properties of the commonly used tungsten/Araldite backings are compared theoretically with those of composites made by pressing Tungsten powder with a powder of a plastic metal.

TL;DR: In this article, the authors proposed an optimized synthetic aperture focusing technique (SAFT) to minimize the level of sidelobes (artefacts) introduced by SAFT, without significant loss of resolution.

TL;DR: In this paper, an analysis of thickness-mode piezoelectric transducer impedance under a variety of mechanical load conditions is presented, where a wideband, systems model is used to describe this impedance, which is representative of the electrical input impedance in the transmitting mode and the electrical output impedance for the receiving mode.

TL;DR: In this paper, the authors describe the design and construction of 10 MHz compressional wave ultrasonic ndt probes for use in situations where operation with the shortest possible pulse length (and hence the greatest bandwidth) is of prime importance.

TL;DR: In this paper, the application of cyclic mechanical loading at 22 kHz frequency significantly modifies the kinetics and dynamics of the individual stages of the precipitation hardening process, and an investigation was initiated where aluminium alloys containing 3.8, 4.1% and 5.2% (weight) copper were aged at a variety of temperatures with and without simultaneous ultrasonic loading at stress amplitudes approaching the fatigue limit of these materials.

TL;DR: A small body of gas which is stabilized against dissolution in a liquid by a supportive structure may oscillate in response to an ultrasonic field and this form of cavitation is termed gas body activation as mentioned in this paper.

TL;DR: Piezoelectric multilayer transducers are constructed in such a way as to produce binary pulse sequences, in particular Barker-coded sequences, achieved by the polarization pattern of the active layers.

TL;DR: In this paper, the authors used a resonant bubble detector (RBD) to detect ultrasonic cavitation at frequencies of 0.514, 0.866, 1.03 and 1.61 MHz.

TL;DR: Test results show that the algorithm can be used to estimate ‘objectively’ the maximum frequency of a spectrum independently of the subjective judgement of the operator and the spectrum analyser gain.

TL;DR: In this paper, the feasibility of selecting the working frequency and mode number of the Lamb wave so that no resonance of the elastic vibrations appears in the weld region is considered analytically.

TL;DR: A pinhole-plate ultrasonic atomizer was proposed and developed in this paper, where a pinhole is joined to a cavity filled with liquid and is vibrated by a circular ring piezoelectric element bonded onto it.

TL;DR: In this article, a pulse generator for multielement ultrasonic transducers with digital control of pulse timing and firing was developed, which can optimize matching to the probe characteristics, and consequently maximize the amplitude of the received echo.

TL;DR: In this paper, an outline of the research carried out into the non-destructive detection of hydrogen embrittlement, whilst it is still reversible, is presented. And a method of determining diffusible hydrogen content has been developed, suitable for samples of the size needed for ultrasonic testing.

TL;DR: In this article, the insertion characteristics of transducers operating in this mode are determined and the compromise between system sensitivity, bandwidth and noise generation in receiving circuits is examined, and the design of suitable generators, based on avalanche operation of one or more bipolar transistors is described in detail.

TL;DR: In this article, an acoustical birefringence method is proposed to measure thickness-varying stresses in slightly orthotropic plates, where off-axis SH-waves at various angles of incidence are propagated in the body's planes of material symmetry, and pass through a common point.

TL;DR: In this paper, it has been observed that the percentage of extraction is greater at lower frequencies: 78% of tannins are extracted in a 40% aqueous acetone solvent using ultrasound in only 30 min compared to 20 h with conventional techniques.

TL;DR: A practical approach for achieving the above specifications is described and illustrations are given for two measuring instruments: an underwater sonar system for quantitative assessment of fish population, and a diagnostic sonar.

TL;DR: A simple device for semiquantitative checking of output power and beam shape has been designed and the beam tester consists of an absorbing plate and a sheath liquid crystal thermometer for temperature distribution display.

TL;DR: In this paper, the reflection coefficient for a bounded ultrasonic beam incident on a liquid-solid liquid system (LSL) is studied and it is shown that the attenuation of the media has a great influence on the variations of this coefficient as has been already mentioned in the literature.